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Commit 2bf0fdad authored by Tejun Heo's avatar Tejun Heo Committed by Linus Torvalds
Browse files

[PATCH] blk: use find_first_zero_bit() in blk_queue_start_tag() 



blk_queue_start_tag() hand-coded searching for the first zero bit in the tag
map.  Replace it with find_first_zero_bit().  With this patch,
blk_queue_star_tag() doesn't need to fill remains of tag map with 1, thus
allowing it to work properly with the next remove_real_max_depth patch.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Acked-by: default avatarJens Axboe <axboe@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 15d20bfd

drivers/block/ll_rw_blk.c

+4 −9
Original line number Diff line number Diff line
@@ -968,8 +968,7 @@ EXPORT_SYMBOL(blk_queue_end_tag); 
int blk_queue_start_tag(request_queue_t *q, struct request *rq)

{

	struct blk_queue_tag *bqt = q->queue_tags;

	unsigned long *map = bqt->tag_map;

	int tag = 0;

	int tag;



	if (unlikely((rq->flags & REQ_QUEUED))) {

		printk(KERN_ERR
@@ -978,14 +977,10 @@ int blk_queue_start_tag(request_queue_t *q, struct request *rq) 
		BUG();

	}



	for (map = bqt->tag_map; *map == -1UL; map++) {

		tag += BLK_TAGS_PER_LONG;



	tag = find_first_zero_bit(bqt->tag_map, bqt->max_depth);

	if (tag >= bqt->max_depth)

		return 1;

	}



	tag += ffz(*map);

	__set_bit(tag, bqt->tag_map);



	rq->flags |= REQ_QUEUED;